Generally, research into a secondary battery capable of being charged and discharged unlike a primary battery has been actively conducted in accordance with the development of state-of-the-art fields such as a digital camera, a cellular phone, a laptop computer, a hybrid automobile, and the like. An example of the secondary battery includes a nickel-cadmium battery, a nickel-metal hydride battery, a nickel-hydrogen battery, and a lithium secondary battery. Among them, the lithium secondary battery, which has operating voltage of 3.6 V or more, is used as a power supply of a portable electronic device or a plurality of lithium secondary batteries are connected in series with each other to thereby be used for a high output hybrid automobile. Since this lithium secondary battery has operating voltage three times higher than that of the nickel-cadmium battery or the nickel-metal hydride battery is more excellent in view of energy density characteristics per unit weight than the nickel-cadmium battery or the nickel-metal hydride battery, the use of the lithium secondary battery has rapidly increased.
The lithium secondary battery may be manufactured in various types. As a typical type of the lithium secondary battery, there are a cylindrical type and a prismatic type that are mainly used for a lithium ion battery. A lithium polymer battery that has been recently spotlighted is manufactured in a pouch type having flexibility. The pouch type lithium polymer battery as described above (hereinafter, referred to as a “pouch type secondary battery”) has a comparatively free shape.
Referring to FIGS. 1 and 2, a pouch type secondary battery 1 generally includes a pouch 2 receiving an electrolyte therein and an electrode tab 3 for electrical connection, wherein the pouch 2 is protected by a case 4 since it may be easily bent or curved. In order to be advantageous in view of a manufacturing cost in configuring a large capacity battery module 10 by stacking a plurality of pouch type secondary batteries 1 and electrically connecting the plurality of pouch type secondary batteries 1 to each other, at least two pouch type secondary batteries 1 are stacked in the case 4, and a partition 5 is disposed between the pouch type secondary batteries 1 so as to stably support the pouch type secondary batteries 1 and prevent a short-circuit of the electrode tab 3.
However, the partition 5 disposed between the pouch type secondary batteries 1 damages a surface of the pouch 2 of the pouch type secondary battery 1 or a gap is generated between the partition 5 and the pouch 2, such that shaking may be generated in the pouch type secondary battery 1 at the time of vibration.